Inform normally produces interactive fiction playable on the Z-Machine, an excellent and well-established format for mostly textual works which are not enormously large. However, it does have limitations, mostly because of its 16-bit rather than 32-bit architecture, and because its sound and graphics support derives from a complicated historical legacy. In the late 1990s, Andrew Plotkin observed that the rival systems for interactive fiction had essentially similar needs, and began work on a common API (i.e., interface by which programs can reach hardware resources) called glk. He then created Glulx, a new platform for Inform-compiled software, which happens to use glk but is really quite a different thing.

The standard Inform compiler (versions 6.30 and later) now compiles to Glulx, as do modified versions of the older 6.21. You also need a recent version of the Inform library. However, to a very large degree your own Inform code will work equally well when compiled to either Glulx or the Z-machine, so the fact that you're using a modified system needn't be very noticeable.

If you are an Inform game author -- reasonably familiar with the Inform language, and compiling Z-code games -- and you want to get into that Glulx thing, then you should read this document first. This probably isn't the only document you should read. This doesn't attempt to cover graphics, sound, or any of the other fancy tricks that Glk makes possible. This guide tries to answer the immediate question: "I have an Inform game, and I want to compile it for Glulx instead of for the Z-machine. What do I do?"

Last updated 16 April 2013. This web site has not been fully supported since April 2008. Information may be out of date. This page was originally managed by Andrew Plotkin.